Thermoregulatory, oxidative stress and lipid responses in prepartum ewes administered with L-carnosine during the hot-dry season.

ABSTRACT

The aim of the study was to investigate the effects of L-carnosine administration to prepartum ewes on oxidative status, lipid profile and thermoregulatory responses in the tropics during the hot-dry season. Twenty pregnant ewes were allotted each into two groups of treated and untreated ewes. The untreated ewes received orally 10 mL of water, while treated ewes were administered orally with L-carnosine (100 mg/kg) daily during the last 3 weeks of gestation. Blood samples were obtained during pre-gestation on day 0, gestation days 136 and 143 and after lambing. Dry-bulb temperatures (DBTs) of the pen were measured once per week at 0600, 1400 and 1800 h as well as the thermoregulatory responses of the ewes. Birth weights of the lambs were determined 2-3 h postpartum. The DBT (37.33 ± 1.20 °C) and temperature-humidity index (85.24 ± 1.91) were above the thermoneutral zone. The results revealed no significant effect of L-carnosine on thermoregulatory responses of ewes and on the live-birth weight of their lambs. Malondialdehyde, 8-isoprostane and triglyceride concentrations were lower (P < 0.05) in treated ewes than in untreated ewes, but superoxide dismutase, catalase and glutathione peroxidase activities were higher (P < 0.05) in treated ewes compared to untreated ewes. In conclusion, L-carnosine reduced lipo-peroxidative products and augmented antioxidant enzyme activities in prepartum ewes under hot-dry conditions.